Why is it easier to believe in the effects of testosterone than it is to show them?

If ever there was a hormone whose discovery was a foregone conclusion it was testosterone. Almost a century before the steroid was isolated Arnold Berthold showed that transplanting testes into castrated roosters restored their characteristically rooster-like behaviour.1 After this, trapping the essence of masculinity in a bottle was only a matter of time.

Time and, for Adolf Butenandt, 25 000 L of urine donated by a Berlin police barracks.2 From this he extracted 50 mg of the weak androgen androsterone and went on to synthesise testosterone and win the Nobel prize for chemistry in 1939. “Dynamite, gentlemen, it is pure dynamite,” he told the Nobel committee (a joke at the expense of the explosive’s inventor).

Between Berthold and Butenandt, however, came the neurologist Charles-Édouard Brown-Séquard. At the age of 72 he delighted the world by announcing that he had rejuvenated himself by injecting aqueous extracts of testes from freshly killed guinea pigs and dogs. A placebo effect, say modern killjoys—little hormone would have dissolved in water. Nevertheless, soon many doctors were treating their male patients with organ extracts.1